In the 1830s Methodist preachers known as "circuit riders" sought to cover large areas of territory, and to bring their religious message to all of the many newcomers to northern Illinois. Jesse Walker, a Virginia preacher first sent to Illinois in 1806, settled at what is now Plainfield in 1829 as head of the Desplaines mission of the Methodists. The stops on the Desplaines and Fox River mission circuits changed each year, and the preachers often shifted their assignments from year to year. In 1835 the Fox River mission included places along the river from Yorkville through Aurora and St. Charles up to Dundee, but also reached east as far as Crystal Lake, Libertyville, Wheeling, and the area now in the Norwood Park neighborhood of Chicago. Stephen R. Beggs,
Pages from the Early History of the West and Northwest, 1868.

Long before the social surveys of the Chicago School of Sociology, the Chicago Bible Society applied to the city a simple question for field research: which families do not have copies of the Bible? The nonsectarian Protestant society, founded in 1840, attempted to canvass the entire city several times in the nineteenth century, although as the city grew it focused its attention on areas considered more likely to be "destitute" of Bibles. It regularly quantified the statistics of its work, including the number of refusals it met with. Chicago Bible Society,
Eighteenth Annual Report, 1858.

After decades of creating geographically defined parishes, in the late nineteenth century the Roman Catholic Archdiocese of Chicago began creating "national" parishes to serve immigrant communities. At the time of the Eucharistic Congress in 1926, the territorial (predominantly Irish) parish of St. Bridget's (#34) in Bridgeport had been joined by numerous ethnic parishes, all a short walk away from each other. These included Immaculate Conception of the Blessed Virgin Mary (#97, German), St. Mary of Perpetual Help (#141, Polish), St. Barbara's (#24, Polish), and St. George (#73, Lithuanian). Cardinal George Mundelein discouraged the proliferation of national parishes after he came to Chicago in 1916. Map of Chicago Showing Location of All Catholic Churches, 1926.

Before there were any church buildings in Chicago, small groups met in private homes and vacant spaces, and some new congregations have continued to begin in this way. Some groups have rented or borrowed space from an established church. Many congregations of small means have adapted spaces built for other purposes, such as vacant storefronts. New Mt. Hermon M. B. Church, 1975.